Antistatic fiber blend

ABSTRACT

A blend of hydrophobic synthetic fibers having improved antistatic properties and improved physical properties consisting essentially of nonshrinkable fibers and shrinkable fibers, and containing 20 to 60 percent of antistatic fibers based on the weight of all the fibers, which antistatic fibers represent all or part of the nonshrinkable fibers, said antistatic fibers being side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkable component side.

United States Patent 1191 Takeya et a1.

1111 3,849,242 Nov. 19, 1974 ANTISTATIC FIBER BLEND Inventors: Kenji Takeya; Kunio Tanahashi,

both of Okayama, Japan Assignee: Japan Exlan Company Limited,

Osaka, Japan Filed: Oct. 13, 1972 Appl. No.: 297,283

Foreign Application Priority Data Oct. 18, 1971 Japan 46-82330 us. 01. 161/176, 57/140 BY, 161/175, 260/1310. 15, 260/D1G. 17, 260/D1G. 21

1m. (:1 D02g 3/00, D02g 3/02 Field of Search 161/175, 176,177; 57/140 BY References Cited UNITED STATES PATENTS 11/1961 Pitts 161/175 X Evans 260/855 3,329,557 7/1967 Magat et a1 161/175 3,350,871 11/1967 Pierce et a1. 57/140 BY 3,388,104 6/1968 Crovatt 57/140 BY 3,400,531 9/1968 Ohfukaet al 57/140 BY 3,626,684 12/1971 Hovis et a1. 57/140 BY Primary ExaminerGeorge F. Lesmes Assistant Examiner-Lorraine T. Kendell Attorney, Agent, or FirmWenderoth, Lind & Ponack [5 7] ABSTRACT 5 Claims, No Drawings ANTISTATIC FIBER BLEND This invention relates to bulky knitted or woven fabrics having improved antistatic properties, excellent hand and physical properties, and are high in their commodity value. Such fabrics are made by using blended yarns in which side-by-side type conjugated fibers are used, and in which antistatic properties are imparted only to the low shrinkable component side of the fibers, and which are used as part or all of the fibers constituting the nonshrinkable fibers forming the bulky knitted or woven fabric. The fabric is composed of nonshrinkable and shrinkable synthetic fibers having a difference in shrinkage of 7 to 40 percent.

Generally, synthetic fibers made from hydrophobic fibers are charged with static electricity when such fibers are processed into various products. The electrical charges on the clothing made from such fibers cause the fabric to stick to the wearer, accumulate dust and, in extreme cases, cause electrical shock.

As methods of preventing the generation of static electricity causing the above phenomenon, there have been already suggested not only a method wherein an antistatic monomer is copolymen'zed in a fiber-forming polymer, but also such various methods as depositing a special antistatic agent on the surfaces of hydrophobic synthetic fibers, a method wherein an antistatic agent is mixed into a polymer so that a durable antistatic property may be imparted to fibers obtained by Further, in order to obtain antistatic fibers, in the fiber producing step or the after-processing step, it is necessary to add at least one step of imparting antistatic properties. Therefore, the cost of the production of said fibers is necessarily greatly increased. As a natural result of the increase of the process cost, bulky knitted or woven fabrics made by using durable antistatic fibers as all of the fibers forming the bulky yarns are so high in price as to be undesirable in industrial practice.

As a result of making hard researches to eliminate such various defects present in antistatic bulky knitted or woven fabrics, the present inventors have reached the present invention by noting that the properties of the surface of bulky knitted or woven fabrics acts as a controlling factor on the charging phenomenon by the friction at the time of wearing said fabrics. That is to say, applicants have discovered that the electrostaticity of the fibers exposed on the surface parts of the fabrics very greatly influences the charging phenomenon of all of said knitted or woven fabrics and that bulky knitted or woven fabrics having sufficient antistatic properties shaping said mixture; a method wherein fibers in an unoriented swollen state are treated with an antistatic agent so that the antistatic agent may penetrate into said fibers; and a method wherein synthetic fibers are treated with a polymerizable antistatic agent or an antistatic agent and a polymerizable compound and then heated to be polymerized so that a water-insoluble substance (or a slightly water-soluble substance) having an antistatic properties may be formed on the surface of said fibers.

However, the introduction of an antistatic monomer having a hydrophilic group into fibers necessarily deteriorates such fiber properties as the strength and elongation and remarkably impairs the hand of the fibers. On the other hand, synthetic fibers to which antistatic properties have been imparted by incorporating an antistatic agent into the fibers, is deteriorated in its elastic recovery properties clue to the antistatic agent present in the fiber structure. Also such fiber becomes coarse and-hard in some cases and, in the extreme case, is remarkably deteriorated in such physical properties as the strength and elongation thereof. Even in the method wherein a substance having antistatic properties is formed on the surface of the fibers, e.g. by coating an antistatic agent on the surface of the fibers, the softness of the fibers are greatly reduced which makes the fibers coarse and hard.

Therefore, knitted or woven fabrics or particularly bulky knitted or woven fabrics made of such antistatic synthetic fibers are deteriorated in their elastic recovery, presenting a coarse and hard touch and, in some cases, deteriorated in such physical properties as the strength and elongation. Although the antistatic properties of the prior art fabrics may be favorable, the fabrics are poor in physical properties such as hand, are not stiff, or are very coarse and hard. This makes them very low in their commodity value.

and remarkably improved in the hand and physical properties can be made by using specific antistatic conjugated fibers only on the surfaces of said knitted or woven fabrics.

A main object of the present invention is to obtain bulky knitted or woven fabrics having practically sufficient antistatic properties.

An object of the present invention is to obtain bulky knitted or woven fabrics which have sufficient antistatic properties are remarkably improved in such physical properties as their hand, stiffness and softness than any conventional knitted or woven products and arc therefore high in commodity value. This is achieved by using blended yarns made by blending side-by-side type conjugated fibers, in which antistatic properties are imparted only to the low shrinkable component side, the

nonshrinkable fibers or a part of them, with shrinkable fibers.

Further, other objects of the present invention will become clear from the following description.

The above mentioned objects of the present invention are attained by knitting or weaving fabrics by using blended yarns which consist of 25 to 85 percent by weight of nonshrinkable fibers and 75 to 15 percent by weight of shrinkable fibers whose difference in shrinkage from said nonshrinkable fibers is 7 to 40 percent and in which antistatic side-by-side type conjugated fibers, whose antistatic property is imparted only to the low shrinkable component side, and which constitutes all of the above mentioned nonshrinkable fibers or one component thereof. The antistatic fibers constitute 20 to percent on the weight of all thefibers.

What is particularly important in the present invention is the kind and the blending ratio of the conjugated antistatic fibers having to be blended into the blended yarns. That is to say, by using side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkable component side and which are used as a part or all of the nonshrinkable fibers and by blending the said conjugated fibers an amount of from 20 to 60 percent by weight of the blended yarns, there is obtained bulky knitted or woven fabrics having practically sufficient antistatic properties and excellent physical properties such as hand, stiffness and softness.

Further, even if such side-by-side type conjugated fibers in which an antistatic property is imparted only to the low shrinkable component side are used as shrinkable fibers or a part of them, no practically sufficient antistatic properties can be obtained. Even in the case where side-by-side type conjugated fibers in which an antistatic property is imparted only to the high shrinkable component side are used as nonshrinkable fibers or a part of them, it will be difficult to develop practically sufficient antistatic properties. Moreover, in the case where side-by-side type conjugated fibers are used in which antistatic properties are imparted not only to the high shrinkable component side but also to the low shrinkable component side, some antistatic properties will be obtained, but no more than in the case where antistatic properties are imparted only to the low shrinkable component as in the present invention. Further, there are still many difficult problems to solve in the quality and economy of the fibers, such as the deterioration of such physical properties of the fibers as the hand and softness and the rise of the production cost due to the large amount of antistatic component necessarily introduced to obtain sufficient antistatic properties.

It is desirable to determine the blending ratio of the shrinkable fibers and nonshrinkable fibers forming the yarns composing the antistatic bulky knitted or woven fabrics in the present invention so as to be in the range of 15 to 75 85 to 25 or preferably 25 to 60 75 to 40 by weight. It is also desirable to determine the difference in the shrinkage between the shrinkable fibers and nonshrinkable fibers so that this difference is in the range of 7 to 40% or preferably 10 to 30 percent.

The shrinkable fibers and nonshrinkable fibers to be used in the present invention are hydrophobic synthetic fibers prepared from vinyl polymers, for example, acrylic fibers, polypropylene fibers, polyvinyl chloride fibers, and the like, and fibers prepared from polymers of polyesters, polyacetals, polyurethanes and polyamides.

The side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkable component used in the present invention are obtained by various well known methods. Generally it is well known that side-by'side (bimetal) type conjugated fibers can be produced by fitting together two kinds of fiber forming components different from each other in their water-reversible shrinkability and/or thermal shrinkability.

For more specific examples of the method and apparatus for the production of such conjugated fibers references may be made to US. Pat. Nos. 2987797, 2988420, 3006028, 3038235-3038240, 3039174, 3039524, 3176342-3176346, 3182106, 3350741, 3403422, 3463846, 3492692, 3515627 and 3540077; Canadian Patent Nos. 791604, 814325, 820777, 857791, etc.

The conjugated fibers to be used in the present invention are those prepared by modifying the fiber forming component so that it is lower than the other in waterreversible shrinkability and/or thermal shrinkability, that is, by modifying the low shrinkable component with a well known antistatic monomer or antistatic agent. The modification may be conducted, for example, in any of the following ways:

1. An antistatic monomer is random, block or graftcopolymerized into a polymer forming a lowshrinkable component. Examples of such antistatic monomers are ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, etc. and their salts such as potassium salt and sodium salt; ethylenically unsaturated sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, etc. and their salts such as a sodium salt and potassium salt; compounds of the following general formula:

wherein R represents H or CH R represents OH, alkoxy having not more than 18 carbon atoms, phenoxy or naphthoxy group, I is a positive integer and m is 0 or a positive integer.

2. A homopolymer or random-, blockor graftcopolymer of the above mentioned antistatic monomer or a mixture of these polymers is mixed into the polymer forming the low shrinkable component.

3. The antistatic agent to be used internally is added into the polymer forming the low shrinkable component. Examples of such antistatic agents are salts of alkyl, cycloalkyl or alkanol amines with an organic or inorganic acid; addition productsof alkyl. cycloalkyl or alkanol amines with ethylene oxide and/or propylene oxide; quaternary ammonium salts; polyalkylene glycols; addition products of alkyl phenols or higher alcohols with ethylene oxide; amine-ethylene oxide addition products; mono-,dior tri-glycerides of higher fatty acids or their ethylene oxide addition products; polyethylene glycol esters of carboxylic acids; higher fatty acid amides or their addition products with ethylene oxide; N,N-dia1kyl amides, etc. The amount of such antistatic agent is generally 05-20 percent, preferably 1-15 percent by weight.

The ratio of the antistatic component contained in the low shrinkable component in such method differs depending on the antistatic component used or the kind of fiber-forming polymer. It is difficult to directly define such ratio, since it is to be determined by the antistatic properties of the composite fibers thus-obtained and on the desired physical properties of the bulky knitted or woven fabrics made from such fibers, such as the hand, stiffness and softness. However, generally it is preferable to select the blending ratio and the kind of the side-by-side type conjugated fibers to be used so that the frictional charge voltage of the bulky knitted or woven fabrics according to the present invention may be not more than 5000 volts. For the side-by-side typeconjugated fibers to be used in this case, it is desirable to adopt such conjugated fibers that the frictional voltage of the knitted or woven fabrics made of only said conjugated fibers is not more than 2000 volts. 1n

this connection, the frictional charge voltage means a maximum frictional charge voltage during 5 .minutes after inducing friction by use of a static machine on a polyester fabric (of polyethylene terephthalate fibers) yarns and it is possible to use side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkable component side and also any other antistatic fibersas the nonshrinkable fibers. However, it is desirable to keep the sum of the amounts of said antistatic conjugated fibers and other antistatic fibers so that they constitute not more than 70% of the weight of the entire knitted or woven fabric.

When the thus obtained knitted or woven fabric an aqueous solution of 45 percent sodium thiocy anate. Spinning solution b.

A solution prepared by adding to the spinning solution (a) glyceryl monostearate inan amount of 5%, based on the weight of the polymer in the spinning solution, as an antistatic agent.

Spinning solution c:

A polymer solution consisting of 12 parts of an made by knitting or weaving blended yarns in which a acrylonitrile-vinyl acetate copolymer (containing specific amount of side-by-side type conjugated fibers 88 percent acrylonitrile) and 88 parts of an aquehaving an antistatic property only on the low shrinkable OUS Solution of 5 P c Sod um hiocyanate.

component side is mixed and spun as nonshrinkable fip n g Solution d bers or a part of them or as a part of shrinkable fibers A Solution prepared by adding to the spinning solutogether with non-shrinkable fibers is heated to de- 15 tion (0) glyceryl monostearate in an amount of 5 velop shrinks, the above mentioned antistatic conjugated fibers will be exposed on. the surface of said knitted or woven fabric. Therefore, the'antistatic properties on the surface of the knitted or woven fabric will be remarkably improved, and the product will possess very excellent antistatic properties which are remarkably improved in such physical properties as hand, stiffness and softness and also be very high in commodity value.

The below mentioned examples are to better explain the present invention but not to restrict the scope of the present invention. The percentages and parts shown in the examples are all by weight unless otherwise specified.

EXAMPLE 1 Single-component fibers or side-by-side type conjugated fibers were made from the below mentioned four kinds of acrylic spinning solutions by the method mentioned in US. Pat. No. 2,558,731 or 3,182,106 to obtain five kinds of acrylic fibers (of a boiling water shrinkage of O to 2 percent) shown in Table 1:

Spinning solution a.

A polymer solution consisting of 12 parts of an acrylonitrile-methyl acrylate copolymer (conpercent based on the weight of the polymer in the spinning solution, as an antistatic agent.

The obtained various acrylic fibers were blended according to such three kinds of blending ratios as in Table 2 to make three kinds of spun yarns. Then three kinds of interlock-knitted fabric were made of the respective spun yarns and were then dipped in boiling water to develop shrinks (to make them bulky). The

shrinkable fibers were made by further stretching fibers 25 E mentioned in Table 1 with a turbo-stapler (to be of a boiling water shrinkage of 25 percent).

The antistatic property of each of the thus obtained three kinds of knittings (I), (ll) and (III) was measured with a static machine manufactured by Takeuchi Elec' tric Machinery Company, Ltd., Japan. The results are shown in Table 2.

The laundering conditions were an amount of a neutral detergent of 2g./l., liquor ratio of 1/200, temperature of 40C. and treating time of 20 minutes by using a commercial washing machine.

As obvious from Tables 1 and 2, it was confirmed that excellent antistatic properties were retained in the knitting (l) in which side-by-side type conjugated fibers where by an antistatic component was introduced only into the low shrinkable component side as nonshrinkable fibers. That is to say, it was apparent that said knitting (I) presented antistatic properties far higher than of the knitting (III) in which were used the fibers C whereby antistatic properties were imparted only to the taming percent acrylonitrile) and 88 parts of 5 high shrinkable component side.

Table 1 Fiber A Fiber B Fiber C Fiber D Fiber E Used spinning solutions (a) (c) (b) (c) (a) (d) (b) (a) Forms of Non-antistatic Conjugated fiber Conjpgated fiber Antistatic Nonantistatic fibers conjugated in which antiin w ich antisingle-composingle-component fiber static properties static properties nent fiber fiber were imparted only were imparted to the low only to the high shrinkable shrinkable component side component side Table 2 Present invention Corn arative exam les Knitting (l) Knitting (ll) Knitting (111) Fiber A 20% 407: 20% Conjugated fibers Fiber B 20% Formations Nonshrink- Fiber C 20% of spun able fibers yarns Single- Fiber D 20% 20% component Fiber E 20% 20% v Table 2 Present invention Comparative examples Knitting (I) Knitting (ll) Knitting (Ill) Shrinkable fibers Fiber E 40% 40% 40% Before laundering 1650 10,000 1900 Frictional charge voltage (in volts) After 2 launderings 2000 l0,000 4200 After 5 launderings 2730 l0,000 5900 Example 2 From the spinning solutions (b) and (d) in Example 1 were made side-by-side type conjugated fibers F in which antistatic properties were imparted to both low shrinkable component and high shrinkable component and side-by-side type conjugated fibers G in which the amount of the antistatic agent in each of the above mentioned two kinds of spinning solutions was cut in half. Then three kinds of blended yarns were made by variously combining said two kinds of conjugated fibers with the fibers A, B and E used in Example 1 and were then made into knittings (IV), (V) and (VI). Their antistatic properties together with the evaluations of the hand are shown in Table 3.

As obvious from the results in Table 3, the knitting (V) in which antistatic properties was imparted not only to the low shrinkable component side but also to the high shrinkable component side contained the antistatic agent in an amount substantially twice as large as 30 in the knitting (IV) according to the present invention but was not remarkably different in antistatic properties. Further, due to the deterioration of the elastic recovery of the fiber F, the knitting (V) was not stiff in hand and was low in the commodity value. It also became apparent that the knitting (VI) made by using the fibers G in which the content of the antistatic agent in the conjugated fiber was made substantially the same as in the fiber B was remarkably inferior in hand and to prepare the product, said antistatic agent being used in an amount of 5 percent based on the weight of the polymer in the spinning solution.

Spinning solution f:

A solution obtained by changing the amount of glyceryl monostearate ethylene oxide addition product in the above-mentioned spinning solution (e) to 10 percent.

Spinning solution g:

A solution prepared by adding to the spinning solution (0) in Example I a glyceryl monostearateethylene oxide addition product (containing 6 mols of ethylene oxide) in an amount of 5 percent based on the weight of the polymer in the spinning solution as an antistatic agent.

Two kinds of blended yarns H and I were made according to the same blending ratio as in Example 2, except that there was used the thus obtained fibers H or I as the antistatic nonshrinkable conjugated fibers in Example 2. Then two kinds of knittings (VII) and (VIII) were made of said blended yarns and their antistatic properties were measured and were shown in Table 5.

As obvious from Table 5, it was confirmed that, in the case wherein the amount of antistatic agent contained in the fibers forming the knitting was equal, and when the antistatic agent was made to exist only on the antistatic properties to the knitting (IV).

Table 3 Present invention Comparative exam les Knitting (IV) Knitting (V) Knitting (VI) Fiber A 20% 20% 20% Conjugated Fiber B 20% fibers Formations Nlonshrinka- Fiber F 20% b e of spun fibers v yarns Fiber G 20% Single component Fiber E 20% 20% 20% fibers Shrinkable fibers Fiber E 40% 40% 40% Before laundering 2020 I900 2400 Frictional charge voltage (in volts) After 2 launderings 2350 2180 3050 Hand of knittings Favorable Not stiff Rather not I enough stiff enough Example 3 Two kinds of side-by-side type conjugated fibers shown in Table 4 were obtained by the same method as in Example 1 by using the below mentioned acrylic spinning solutions (e) to (g) and the spinning solution (c) in Example I:

Spinning solution e:

A solution prepared by adding to the spinning solution (a) in Example I a glyceryl monostearateethylene oxide addition product, as an antistatic agent, wherein 6 mols of ethylene oxide are used low shrinkable component side of the side-by-side type conjugated fibers, higher antistatic properties were ob tained. Further, in respect to the hand, the knitting (VIII) made by using the conjugated fibers in which an antistatic agent was present in both components presented an appearance which was thin and poor in its voluminous feeling, whereas the knitting (Vll) made by using the conjugated fibers in which an antistatic agent was added only on the low shrinkable component side according to the present invention was high in voluminous feeling (thick feeling) and had a high commodity value.

Table 4 Fiber H Fiber I Used spinning solutions (f) (g) Forms of antistatic 5% antistatic agent fibers agent was added was added uniformly only on the low on each of the low shrinkable component shrinkable composide nent side and high shrinkable component side Table 5 Present Comparative invention example Knitting Knitting (Vll) (Vlll) Used conjugated fibers Fiber H Fiber 1 Frictional Before laundering 840 i570 charge voltage After 2 launderings i300 2140 (in volts) After 5 launderings 2010 2860 What we claim is:

1. A blend of substantially all acrylic synthetic fibers having improved antistatic properties and improved physical properties consisting essentially of 25 to 85 percent by weight of nonshrinkable fibers and 75 to percent by weight of shrinkable fibers having a difference in shrinkage of 7 to 40 percent from said nonshrinkable fibers, and containing 20 to 60 percent of antistatic fibers based on the weight of all the fibers in the blend which antistatic fibers constitute all or a part of the nonshrinkable fibers, said antistatic fibers being side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkage com ponent side.

2. The product of claim 1 wherein the low shrinkable component side of the side-by-side type conjugated fibers has applied thereto 0.5 to 20 percent of an antistatic agent based on the weight of the low shrinkable component.

3. The product of claim 2 wherein said antistatic agent comprises monoglycerides of higher fatty acids or their ethylene-oxide adducts.

4. The product of claim 1 wherein said blend of fibers is in the form of a bulky textile yarn 5. Bulky textile goods comprised of a blend of substantially all acrylic synthetic fibers having improved antistatic properties and improved physical properties consisting essentially of 25 to 85 percent by weight of nonshrinkable fibers and to 15 percent by weight of shrinkable fibers having a difference in shrinkage of 7 to 40 percent from saidnonshrinkable fibers, and containing 20 to 60 percent of antistatic fibers based on the weight of all the fibers in the blend, which antistatic fibers constitute all or a part of the nonshrinkable fibers, said antistatic fibers being side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkage component side. 

1. A BLEND OF SUBSTANTIALLY ALL ACRYLIC SYNTHETIC FIBERS HAVING IMPROVED ANTISTATIC PROPERTIES AND IMPROVED PHYSICAL PROPERTIES CONSISTING ESSENTIALLY OF 25 TO 85 PERCENT BY WEIGHT OF NONSHRINKABLE FIBERS AND 75 TO 15 PERCENT BY WEIGHT OF SHRINKABLE FIBERS HAVING A DIFFERENCE IN SHRINKING OF 7 TO 40 PERCENT FROM SAID NONSHRINKABLE FIBERS, AND CONTAINING 20 TO 60 PERCENT OF ANTISTATIC FIBERS BASED ON THE WEIGHT OF ALL THE FIBERS IN THE BLEND WHICH ANTISTATIC FIBERS CONSTITUTE ALL OR A PART OF THE NOSHRINKABLE FIBERS, SAID ANTISTATIC FIBERS BEING SIDE-BY-SIDE TYPE CONJUGATED FIBERS IN WHICH ANTISTATIC PROPERTIES ARE IMPARTED ONLY TO THE LOW SHRINKAGE COMPONENT SIDE.
 2. The product of claim 1 wherein the low shrinkable component side of the side-by-side type conjugated fibers has applied thereto 0.5 to 20 percent of an antistatic agent based on the weight of the low shrinkable component.
 3. The product of claim 2 wherein said antistatic agent comprises monoglycerides of higher fatty acids or their ethylene-oxide adducts.
 4. The product of claim 1 wherein said blend of fibers is in the form of a bulky textile yarn.
 5. Bulky textile goods comprised of a blend of substantially all acrylic synthetic fibers having improved antistatic properties and improved physical properties consisting essentially of 25 to 85 percent By weight of nonshrinkable fibers and 75 to 15 percent by weight of shrinkable fibers having a difference in shrinkage of 7 to 40 percent from said nonshrinkable fibers, and containing 20 to 60 percent of antistatic fibers based on the weight of all the fibers in the blend, which antistatic fibers constitute all or a part of the nonshrinkable fibers, said antistatic fibers being side-by-side type conjugated fibers in which antistatic properties are imparted only to the low shrinkage component side. 